Factors associated with persistent urinary incontinence

OBJECTIVE: Many women with urinary incontinence (UI) have symptoms that continue over many years; however, virtually nothing is known about factors that are associated with persistent UI. STUDY DESIGN: We studied 36,843 participants of the Nurses' Health Study, aged 54-79 years at baseline for the UI study, who provided UI information on biennial questionnaires from 2000 through 2008; follow-up in the Nurses' Health Study is 90%. In total, 18,347 women had "persistent UI," defined as urine leakage >= 1/mo reported on all 5 biennial questionnaires during this 8-year period; 18,496 women had no UI during this period. Using multivariable-adjusted logistic regression, we estimated odds ratios (ORs) of persistent UI vs no UI across various demographic, lifestyle, and health-related factors, which were derived from reports in 2000. RESULTS: Increasing age group, white race, greater parity, greater body mass index (BMI), and lower physical activity levels were each associated with greater odds of persistent UI, as were several health-related factors (ie, stroke, type 2 diabetes, and hysterectomy). Associations with persistent UI were particularly strong for increasing age group (P trend < .0001; OR, 2.75; 95% confidence interval [CI], 2.54-2.98 comparing women aged >= 75 vs < 60 years) and greater BMI (P trend < .0001; OR, 3.14; 95% CI, 2.95-3.33 comparing women with BMI >= 30 vs < 25 kg/m(2)); moreover, black women had much lower odds of persistent UI compared to white women (OR, 0.27; 95% CI, 0.21-0.34). CONCLUSION: Factors associated with persistent UI were generally consistent with those identified in previous studies of UI over shorter time periods; however, older age, white race, and obesity were particularly strongly related to persistent UI.